Vaporizing apparatus and means for controlling the vapor pressure thereof



May 16, 1933. w. H. ALLEN El AL VAPORIZING APPARATUS AND MEANS FOR CONTROLL ING THE VAPOR PRESSURE THEREOF Filed July 20, 1929 @atented May 16, 1933 UNITED STATES PATENT OFFICE WILLIAM H. ALLEN, CHARLES F. RITCHIE, AND WILLIAM A. GALE, 0F TRONA, CALI- FORNLA, ASSIGNORS TO AMERICAN POTASH 8a CHEMICAL CORPORATION, OF TRONA, CALIFORNIA, A CORPORATION OF DELAWARE varomznve arranarus AND MEANS FOR CONTROLLING THE VAPOR PRESSURE THEREOF Application filed July 20,

This invention relates to a vaporizing apparatus and a device for controlling the vapor pressure of such apparatus. The invention has been found of particular value in controlling the vapor pressure of cooling apparatus, which operates by reduced pressure to cool the liquid by vaporizing a portion of the liquid.

The major object of the present invention is to provide a vaporizing apparatus in which the vapor pressure maintained within the apparatus may be automatically controlled to' of apparatus embodying the invention. For

this purpose there is hereafter described a preferred form or example of an apparatus embodying the invention. The description is given inconnection with the accompanying drawing, in which Figure 1 is a diagrammatic view of an apparatus embodying the invention in which a reduced pressure or vacuum is employed on the vaporizing chamber.

Figure 2 is an enlarged diagrammatic view of the pressure controlling device.

Referring to the drawing: While the invention is not limited necessarily in all of its broad aspects to any particular, style of vaporizing chamber in which pressure is to be controlled in order to clarify the restriction of the invention, a specific form is shown in which 2 indicates a vaporizing chamber 1929. Serial N0. 379,858.

into which a line 3 discharges for introducing continuously, if desired, liquid which is to be subjected to partial vaporization and preferably also cooling on account of such vaporization. 4 indicates a line by which the liquid may be withdrawn from chamber 2 by means of a pump 5. Chamber 2 is provided with the vapor line 6 leading to a condenser coil 7 of any preferred or customary type, hence to a receiver 8 which is provided with a line 9 leading to a vacuum pump 10. The condenser coil may be replaced with any other suitable equipment, such as a standard barometric condenser.

No claim is made herein to the use of the surface condensing coil 7 in the outgoing vapor line 6 of the vacuum evaporatin chamber 2, said invention being described and claimed in the co-pending application of Burke, Allen, Ritchie, Gale and Feet, filed September 6th, 1932, Serial No. 631,792.

In operation of the apparatus, liquid under atmospheric or superatmospheric or partial sub-atmospheric pressure is introduced into the line 3, into the vessel 2 and there the pressure is reduced in order to effect a vaporization of part of the contents of said liquid. The main liquid is withdrawn from line 4 and the vapors passed off through line 6 are condensed in container 7 and passed to receiver 8. It is the purpose of the invention to equally control the absolute pressure of the vapors in vapor space of vaporizing chamber 2. For this purpose, such vaporiz-- ing chamber 2 is shown as provided with a line 11 leading to a vapor pressure controlling device 12. The line 11 is shown as provided with a vent line 13 leading to the atmosphere or other suitable source of air supply by which air may be admitted to the apparatus, thereby increasing the pressure therein.

The pump 10 in operation is normally 0perated to remove noncondensable gas so as to insure a greater vacuum-0r reduced pressure on the apparatus than is desired; and the valve 13a is relied upon to admit air or other suitable noncondensable gas at a rate in excess of the capacity of the vacuum pump 10, to hold the vapor pressure at the desired point. A device 12 is intended to automatically operate the valve in the vent line 13 to accomplish this result.

Generically considered, the device 12 comprises a closed vessel 14 which contains a column of conducting liquid 15 connected at its upper end as indicated at 16, to the line 11 so that the height of liquid in the column fluctuates with variations of pressure within the chamber 2. The device thus operates as a manometer.

Pipe 11 is shown as entering an upper metallic block 17 which is connected to the lower metallic tube 14 by a non-conducting electrical joint 18. The bottom of the chamber 14 terminates in a receptacle 19. The liquid may, for example, be mercury, and in such a case the receptacle 19 is a mercury reservoir. The receptacle 19 is of a conducting material or metal and has a means 20 by which an electrical line 21 may be connected therewith so as to establish electrical connection with the liquid column 15. A screw 22 is provided entering the block 17 and extending axially downward to be in position to contact with the mercury column 15 when the mercury column is drawn up by vacuum in line 11 to a predetermined position. A line 23 is connected with metallic block 17 as indicated at 24:.

Preferably there is provided a small carbon block 25 floating on the top of the mercury column for the purpose of making the actual contact with the set screw 22. The use of carbon block onthe top of the mercury column prevents vaporizing of mercury by the spark when contact is made and broken. When contact is made between set screw 22 and carbon block 25, a circuit is made through switch 26 and lines 23 and 21 through a solenoid 27. The solenoid .27 contacts with a valve 28 which controls the inlet of air from the vent line 13. With the admission of air, the vacuum in chamber 2 falls slightly, the mercury column 15 drops, breaking contact with set screw 22, the valve 28 is consequently released by the solenoid and drawn back to its seat by vacuum. The vacuum increases and the mercury column again rises until I contact is made with the block 25 and the sequence in operation is repeated.

With proper adjustment of the temperature of the condenser water, air removal and well proposed area of valve 28, close pressure and temperature control is secured where contact is made and broken by slight changes in vapor pressure in chamber 2.

To make this control even more delicate, an electrical conducting liquid lighter than mercury may be used.

The container 19 in Figure 2 may be open at the top to the atmosphere, in which case the regulation pressure will be affected by variations in atmospheric pressure. Where a more accurate regulation is desired, the chamber 19 may be closed, in which case it should be of considerable size and be capable of holding many times (say 100 times) the cubical contents of the tube 1 1. In such a case, the regulation of pressure by the apparatus will be independent of the atmospheric pressure and will provide extremely accurate regulation.

The apparatus thus described furnished an effective means for admitting noncondensable gas to the vaporizing chamber at an inter mittent rate and also provides a means for continuously removing such noncondensable gas from the condensing zone. The control of pressure or vacuum in the apparatus is dependent, in the case of a surface condenser, upon the blanking of]? effect of this noncondensable gas. By supplying the noncondensable gas at rates in excess of which the gas can be removed by the vacuum pump and interrupting the rate of supply of such gas, a very efiective pressure or vacuum con trol is obtained.

While the apparatus herein illustrated is well adapted to carry out the objects of the present invention, various modifications and changes may be made without departing from the principles of this invention and this invention includes all such modifications and changes as come within the scope of the appended claims.

We claim:

1. An apparatus of the class described comprising a vaporizing chamber, a condensing chamber connected with the vaporizing chamber, means for admitting noncondensable gas to the vaporizing chamber at an intermittent rate suitable to maintain a constant pressure within said vaporizing chamber, and means for continuously removing the same from the condensing chamber.

2. An apparatus of the class described comprising a vaporizing chamber, a condensing chamber connected with the vaporizing chamber, means for supplying non-condensable gas to the vaporizing chamber, means for continuously removing the noncondensable gas from the condensing chamber, means for supplying the noncondensable gas to the vaporizing chamber being capable of supplying more gas than can be removed from the condensing chamber, and means for interrupting the rate of supply of gas to the vaporizing chamber so as to obtain a substantially uniform pressure therein.

3. An. apparatus of the class described comprising a vaporizing chamber, a condensmg member connected therewith, means for removing noncondensable gases at a uniform rate from said condensing member, and

means for supplying noncondensable gases at an intermittent rate to the vaporizing chamber, and means for regulating the intermittent supply of noncondensable gas to the vaporizing chamber to maintain substantially constant the pressure therein.

Signed at Trona, California, this 8th day of July 1929.

WILLIAM ,H.ALLEN. CHARLES F. RITCHIE. WILLIAM A. GALE. 

